LHC Progress Thursday 29 th October 2015 Coordination Week 44: Massimo Giovannozzi, Wolfgang Hofle, Jorg Wenninger

LHC Progress Thursday 29th October 2015

Coordination Week 44:Massimo Giovannozzi, Wolfgang Hofle,

Jorg Wenninger

LHC Morning meeting – WH & JW 2

Wednesday, 28th October 2015 • Fill 4540 (SB 12h30’)– First fill with 2244 bunches– Intensity on low side, emittances on high side

• 4.2x1033 peak lumi (ATLAS)

• 12:40 Bunch flattening at 1 ns bunch length• 15:00 OP dump (clean)• 16:00 MKI.B1 & PS cavity (total 30’)• 17:00 injecting probe beam– Quick cryo stabilisation after dump

• 18:00 ramping for loss maps in preparation of quench test MD, nominals + probes– Relaxed settings for IR7, IR6

29/10/2015


Wednesday, 28th October 2015 • 2nd ramp needed– beam lost at flat top while moving collimators (SBF

setting not correct)• 21:20 strength of ADT for loss maps insufficient

for V plane for opened collimator, ADT expert called (G. Kotzian) – 20 MHz flat bandwidth filters implemented for the

cleaning reduce peak kick strength– Gerd loaded filters coefficients to permit higher kick

strength– Reverted by OP after loss maps

• Finished with a beam 2 off momentum loss map29/10/2015


Wednesday, 28th October 2015 • Fill 4545 (SB 3h)

– 2nd Fill with 2244• 4.8x1033 peak lumi (ATLAS)

– Preparing takes time (1h50), steering lengthy (1 train of 12 only)– TDI B1, losses: 70% of dump threshold– higher bunch intensity than Fill 4540– 10% more heat load than 4540 (same #bunches)– Point 2 cryo cold box emptying quickly (stabilised at 46%)– Q feedback and cleaning interference in squeeze– Lumi scans IP1 and IP5 not correctly stopping at max

• 6:20 Totem Roman pots in • 7:05 dumped by CIB.USC55.R5.B1, 120 A (orbit correctors)

– RPLB.RR57.RCBCH9.R5B1

29/10/2015


Wednesday, 28th October 2015

29/10/2015

>1.1x1011 p/bunch Before ramp: 3 mm

Fill 4545 (2244 bunches)


Last 24 h

29/10/2015

4.8x1033 peak (ATLAS)

4540 4545


Bunch Flattening (fill 4540)• bunches were flattened in the core without losses• bunch profiles are more symmetric on B2• FWHM bunch length increased from 1.0 ns to 1.42

ns (B1) and 1.32 ns (B2)• there is a step in luminosity during the application

of the flattening• evolution of luminosity with flattened bunches to be

observed and compared to Gaussian bunches• bunch profiles to be observed again before dumping

29/10/2015

RF Team

Reminder: Fill 4538, bunches unstable below 0.85 ns length increasing steadily


Bunch Flattening

29/10/2015

some reduction on lumi seen 5% / ~ 0.15x1033

but no optimization (lumi scan done)to be checked what fraction from abort gap cleaningfrom geometric factor or simply offset

3x1033

2x1033

ATLAS

CMS


Fill 4540

29/10/2015

preliminary

Bunch lengthLumiCleaning beam 1


Availability 24h

29/10/2015

4540 (OP dump)(2244b)

4545 (2244b)

MKI B1

PS (RF)

Preparation of Quench test MD(Loss maps)


Issues in IP2 – Fill 4540

29/10/2015


Plan • Continue with 2244b, bring back bunch intensities done• Preparation of quench test MD: loss maps with relaxed

collimator settings done, check loss maps• Test of 2.51 TeV cycle - settings ready next

• Second test with asymmetric filling (1825b in B2, 12b in B1)• BCMS when CMS is back MD• End of run last minute test requests roll in:

– Injection with inverted tunes (0.31/0.28) to understand the source of electron cloud (dipoles/quads) – e-cloud team.

– 50 Hz from PCs – G. Arduini

29/10/2015

LHC Morning meeting – WH & JW

To do list

29/10/2015 13

8b4e Done short fill SB & 1593b to FT

BCMS Type test

ADT full bandwidth GA request skip ?

ULO scan Towards the end

Reference heat load Before TS3

Check deconditioning at 450 GeV After TS3

Heat load with single beams to FT B1 done, B2 1824b with wire scans in B1 with 12 bunches

Bunch flattening tests in SB Done

First look at 2.51 TeV Prep. for pp reference run

Doublet Pushed to 2016

Documents

LHC Progress Thursday 29 th October 2015 Coordination Week 44: Massimo Giovannozzi, Wolfgang Hofle, Jorg Wenninger